1. Field of the Invention
The invention relates to a device for transmitting tensioning forces to printing-unit cylinders, especially in rotary printing presses having printing-unit cylinders carrying or guiding areal, i.e., primarily two-dimensional, flexible dressings or packings.
2. Description of the Related Art
In German Patent 1 279 689 representing the state of the art, a device is disclosed for locking a tensioning rod of a roller packing or covering, more particularly, an impression-cylinder packing of a letterpress. A switch provided on the tensioning rod has a pawl or latch rotatable about a pin. The latch, which has a spring force applied thereto, engages in a control wheel which determines the position of the tensioning rod which applies tension to or releases tension in a deposit or covering on a printing-unit body. The value or level of the holding momemt which this heretofore known device can transmit or maintain is limited, however.
German Patent 10 75 635 discloses a device for tensioning the packing on impression cylinders. A worm gear is fastened to a tensioning rod at an end face of an impression cylinder, and cooperates with a screw or worm mounted in a housing.
The worm gear is thus seated on the tensioning rod which accommodates both a front or leading edge and a rear or trailing edge of the packing or covering. The device of this German patent does not exhibit any feature which offers exchangeability of the worm wheel.
It is accordingly an object of the invention to provide a device for optimally transmitting tensioning forces to printing-unit cylinders so that high turning moments or torques are transmissible, and disassembly with minimal space requirement is realizable.